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Mailbag: LID and NU

We received this email a few weeks ago and I wanted to take the time to answer it here.


I’d like your opinion on what seems to be a discord between practitioners and advocates of LID, Low-Impact Development or Green Infrastructure, techniques to manage stormwater and water quality, and practitioners and advocates of New Urbanism.

Both seem to be viable alternatives to our current patterns of development, land and resource use. Although, my concern with the latter is that it often ends up producing only very expensive housing.

In any case, LID is an essential component in moving into a sustainable future.  It also fits quite well with returning roads to community streets.  There really should be no contention or disagreement between LID and New Urbanism.  It would be unfortunate if this chasm were to continue unnecessarily.

Thank you,

Ann P.

I may disappoint you, Ann, along with others who may hold Low Impact Design and Green Infrastructure in high esteem. I have no such inclination myself.

First, let's get on the same page as to what is meant by Low Impact Design (LID) and Green Infrastructure. Both are very concerned with the management of stormwater, with a secondary concern (and my experience has been that this is a FAR secondary concern) being habitat preservation. From Wikipedia (which I think is fairly accurate), some of the benefits of LID are described as:

...protecting animal habitats, improving management of runoff and flooding, and reducing impervious surfaces. LID also improves groundwater quality and increases its quantity, which increases aesthetics, therefore raising community value.

LID can also be used to eliminate the need for stormwater ponds, which occupy expensive land. Incorporating LID into designs enables developers to build more homes on the same plot of land and maximize their profits.

My skepticism toward LID is based on my observation of how it has been applied. 

First, I see LID being applied almost exclusively to new projects, which are largely themselves on greenfield sites. The stormwater ponds and other such approaches are used to mitigate the negative impacts of the development. This is a sub-optimal outcome because, in almost every instance I have ever seen, the development is the result of a series of government policies that favor greenfield development.

These tend to be poor compromises that ultimately have little impact. Over time, stormwater areas made with pervious pavers or other pervious materials lose their capacity. Ultimately they will fail. There is no mechanism built into any local bureaucracy for measuring their rate of decline or replacing them with materials of similar performance once they do fail. So we ease our conscience a little bit when we require these things, but long term, it only enables bad development.

Which is really the main reason why I have no love for LID. I can't tell you how many times I have been at a meeting where a developer comes in with a terrible project that has been "greenwashed" (I don't like the term, personally, but it makes the point here) by having all of the LID elements in place. Or the LEED certification, for that matter. (Check out Kaid Benfield's post on how the EPA pulled this on their new remote campus in Kansas City). At that point, we're just mitigating negative impacts. I prefer avoidance.

So how would we avoid them in the first place? Well, since we have more infrastructure than we have the capacity to maintain by a startling margin, I would focus development on our core cities where we already have the infrastructure investments in place. Unfortunately, the LID advocates often oppose that type of development as well.

I often point out how the new, sprawling campus that the county built in my hometown comes complete with a nature band aid; rain gardens in the middle of the downtown. Personally, I would rather use that space to build some good urban structures that could house people and businesses and take some of the pressure off the real wetlands we are filling on the periphery of town. (In fact, it should be noted, I would end all of the subsidies of those structures on the periphery and, if that were done, few would ever be built.)

Again, I can't tell you how many meetings I have been at where the LID advocates show up and demand certain checklist items, not understanding the overall context of the site. The two block comparison I wrote about to start the year is a prime example. You have a project that devolved the city, eroded the tax base, reinforced the auto-dependency of the community and the environmentalists were happy with it because it had stormwater retention ponds. That's one dimensional thinking, and it's not good enough.

So I think LID enables the worst kind of development, and really is not that low impact over the long run. Yes, if you insert me into a design review process where the site is set, the building is set and all we are doing is reviewing their site plan, I would push for all of the mitigation efforts I could. Great, but that is a little like Moses advocating for condoms once someone decides to commit adultery. There is a reason the ten commandments are short; they are not encumbered with a lot of nuance. 

Maybe we need nuance, and if we do, LID can be it. As for is being a governing philosophy or an optimal approach, it is clearly not.

Neither is New Urbanism, for that matter. At least not the "build a better suburb" type. But if you had been in West Palm Beach last week hanging out with me and the other NextGen of the New Urbanists, you would see that the better bad approach is completely out of favor. There is little tolerance amongst the new flock for the lesser of two evils. Amen to that.

I would strongly recommend reading the work of Steve Mouzon, particularly his book The Original Green. In that, he talks about the way our ancestors used to live and, guess what, it was a lot softer on the environment than what we do today (gadgets, gizmos, gimmicks and all).

Our cities are in the early stages of contraction, with exurbs being the first place where it is really manifesting itself. (Incidentally, I'll be on Minnesota Public Radio this Friday talking about the future of the exurbs -- 9AM CST at I don't want LID to get in the way of building productive places within our core cities and neighborhoods. Concurrently, I want our countryside to return to the low impact pattern of development that dominated North America until recent decades. I think both are likely to start happening as soon as we come to grips with the fact that we can't afford to fix our highway system.

Ann, I know your question was asked with all sincerity. I think we want the same thing and I hope that my lack of support for LID does not keep you from working to build a strong town.

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Reader Comments (7)

Wow! The ten commandments analogy is spot on! As you say, LID sometimes becomes an apology or an enabler of bad development. I couldn't agree more. The most advanced LID I've ever seen was for an enormous mixed-use village center in Alabama. The developer basically offered LID and a few other band-aids as compromise (or distraction) for locating the development so far away from the City core. The logic of the council went something like "Well, it's way out there and requires a mile of sewer but, hey, it's got LID! It's green!"

Very well said. Oh, and some LID aspects are still very much in the proving stage. I've seen lots of porous concrete crumble after hard freezes.

May 16, 2012 | Unregistered CommenterNorm

Great to see you in WPB. Totally agree with your take on this. I very much support the light touch methods as tactics when appropriate within a project, but just as a tactic. The strategy remains contraction and the infill or redevelopment of the properties within, instead of outside. Once the right place has been selected, only then can it make sense to implement mitigating measures that reduce adverse impacts. I have seen projects that would be in the right place opposed on the basis that they don't have the capacity to integrate light touch water management practices and I have seen projects proposed in the wrong place supported because of the presentation of light touch water management practices. Part of this is embracing nifty ideas that simply happen to be totally inappropriate. I recently had to argue with a client, who is enamored with LEED, who wanted to get a point for installing rain chains; slight problem in the Northeast, with freezing winters. I had to explain that he would end up with 25 foot icicles. Right now, many of the documents that present good methods and practices fail to create a hierarchy for proper implementation. We need to start with context and differentiate between strategies that can lead us to the right place and tactics, which can help us once we get there.

May 16, 2012 | Unregistered CommenterPaddy Steinschneider

You know, I realized that someone could read that line about the countryside and "returning" to a light footprint and get the wrong impression. Let me clarify.

Prior to the Suburban Experiment, we did not exactly have a light footprint on the landscape. In my state of Minnesota alone, farmers filled in half of the wetlands. Few of them have been restored and more are filled each year. This was anything but low impact.

What I really want to focus on here is our building. Across the landscape pre-Suburban Experiment there was little development and what there was concentrated in and near cities and towns or was very small scale. Habitat fragmentation by highways and subdivisions was not an issue. This was not no impact, but by comparison, it was a much lighter footprint than a wholesale conversion to LID would bring about.

May 16, 2012 | Unregistered CommenterCharles Marohn

There's certainly some aspects of LID that are admirable, and are even quite useful in an urban environment. Things like green roofs or roof gardens, permeable paving, or even roof rainwater harvesting are quite appropriate in highly built-up areas. The trick is to find the "old way" of implementing such things, because nowadays most of these solutions are vastly over-engineered to the point of absurdity. For instance, instead of having a simple rain barrel that the downspouts funnel into, we'd have engineers or code officials insisting on having bypass valves for the first flush of water, filters to treat the water for particulates or algae growth, pumps to pressurize a hose instead of using a watering can, etc.

I can think of some good examples of both the good and bad approaches here in Cincinnati. In Over-the-Rhine, the 19th-century rowhouse neighborhood north of downtown, there's a handful of alleys, most of which still have original brick paving and concrete curbs. They're impossibly narrow though, so their usefulness is greatly restricted. In one particular stretch, the city came in and dug up the bricks, put in a new gravel base, and reinstalled the bricks with a little more space between them and also brought them up to be flush with the curbs. This made the alley a little wider so it's easier to fit a car or truck through it, but the spaces between the bricks allows rainwater to permeate. This is a simple and effective strategy for rehabilitating some valuable infrastructure that makes it not only more useful, but gets some green points too.

Another example is some stretches of road that got rebuilt with rain gardens. One particular example (Spring Grove Avenue) is certainly a lot nicer looking than it used to be, as there's now essentially a bio-swale between the curb and the sidewalks and also a small landscaped median instead of concrete and asphalt in an unbroken section. However, the amount of engineering and extra building (the island's curbs, multiple inlets and overflow drains in the swales, etc.) plus the small size of the vegetated area suggests a very poor return on the amount of investment. The Oakley neighborhood business district streetscaping project is similar. There's some rain gardens, which are basically sunken tree planters with inlets from the curb, and some permeable paving. Again, there's a lot of concrete construction and engineering involved, and the amount of runoff that these systems capture can't be all that significant.

Still, roof gardens or green roofs are pretty easy to achieve, and they have other benefits beyond capturing rainwater, such as improving roof insulation, evaporative cooling, and shading. Nevertheless, the simplest and most effective way to be green is to live in a compact, walkable neighborhood, with buildings built side-by-side and up to the street. When you do this, you don't need to mitigate your impacts because your footprint, while rather "heavy" on the land, is incredibly small. In such a place you don't need useless "green space" to buffer your building or yourself from the surroundings because you're in a place scaled to and built for the interface of people, not cars roaring by. This is a simple and very efficient, not to mention sustainable and resilient, pattern of living that has been virtually unchanged throughout the course of human history, at least until the industrial revolution came along. Andres Duany likes to say that we need a "LEED Brown" rating for such development, because when you build the buildings side-by side and have a pleasant walkable neighborhood, then you don't need triple-glazed argon-filled low-e windows, or 8 inches of closed-cell spray foam insulation, or a geothermal heat pump HVAC system, or retention ponds, or landscape buffers, because you don't have to mitigate the impact of a stand-alone building that's so much more exposed to the elements and that you have to drive to.

May 16, 2012 | Unregistered CommenterJeffrey Jakucyk

oh amen brother!

the backwardness of thinking its better to build a fraction as many units on a parcel, in pursuit of LID, pushing the remaining market further and further out, taking up exponentially more land and environmental resources in providing new infrastructure (that you eloquently prove time and time again we can't afford), it's just an astounding breakdown of logic, or, more likely, yet another salve to make people feel ok about structural waste.

May 16, 2012 | Unregistered Commenteradam.

This discussion is an opportunity to throw something out there. One point of Ann's critique is that new urban projects are expensive. I have observed that the great old urban neighborhoods are also too expensive. I think it is because we stopped making them. After listening to part of a great economics podcast yesterday I solidified my belief that new projects being expensive is not a bad thing at all. It is an affirmation that urbanism is a convenient truth. There is a paradox of opportunity here because the most desirable places are not over-gentrified mono cultures, "elites only". They are quirky and socioeconomically diverse. They are so damn expensive because they are so rare...."just build more strong towns right?"
Am I oversimplifying this?
I sense that some ST skeptics come away from a chat with a doom and gloom outlook and yet there is real proof in the economics that we will be much happier people with more traditional neighborhoods available.

May 16, 2012 | Unregistered CommenterErik B

Erik, there's definitely a very strong supply and demand issue. Because of draconian zoning and other building code restrictions, there's an oversupply of suburban development, while little new urban development is being done. Thus, there's not enough supply of good urbanism, so the price for what there is soars.

Of course there's little demand for bad urbanism either, and issues of schools and crime and such are in most cases independent of the built environment. So there's other forces that conspire to keep the supply of viable urban neighborhoods limited, thus putting even more pressure on the few that are left. When already nice neighborhoods can't densify, and new dense development can't be built, then it creates scarcity, which thus drives up the price, and the demand can only be partially satisfied by more sprawling development out on the fringe.

May 16, 2012 | Unregistered CommenterJeffrey Jakucyk
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